This invention concerns an image forming apparatus by which a toner image is formed on an image carrying member by an electrophotographic method and is transferred onto a transfer material to obtain an image. This invention specifically concerns an image forming apparatus such as a printer, a copier, or a facsimile which incorporates a process cartridge, in which is integrally provided an image carrying member and at least one of developing means and cleaning means.
Image forming apparatuses are becoming increasingly complex with their declining size and weight, as well as the more advanced functions of apparatuses such as printers and copiers. On the other hand, image forming apparatus equipped with a process cartridge that combines at least developing means or cleaning means with an image carrying member have been developed in order to enable unskilled operators to perform maintenance and management easily.
Image forming apparatuses such as printers and copiers which possess this process cartridge are designed to be used by operators who do not have technical knowledge, who can easily perform maintenance and management of the image forming apparatus when the image carrying member inside the process cartridge is exhausted or depleted. For this purpose, a guide member for the process cartridge is provided to the apparatus so that correct loading, in which an optimum image can be obtained, is realized by simply inserting the process cartridge along this guide member. In conventional apparatus, the direction of handling the process cartridge and the direction of handling materials were different in fact crossing at right angles, which, in turn, not only made work troublesome but created an inevitable spatial limitation for installing an image forming apparatus. Furthermore, much space was required for maintenance work.
Patent Application Laid Open No. 61-279870 was proposed to solve these problems. An image forming apparatus which is capable of simplifying handling and operation of expendables and reducing limitations of work space by matching the loading direction of materials and the loading/unloading direction of the process cartridge installed on the upper frame has been proposed.
However, the image forming apparatus disclosed in Patent Application Laid Open No. 61-279870 requires opening of the upper frame for an operator to pull out and remove the process cartridge from the upper frame when replacing the process cartridge. For this reason, not only is this work very troublesome but requires considerable force on the part of the operator if the process cartridge is heavy or bulky. Furthermore, it is necessary for an operator to put his hand into a small space to remove transfer materials when a jam occurs, and such jam procedure work is difficult as sufficient work space cannot be secured, no matter how far the upper frame is opened. Moreover, the operators hand sometimes comes into direct contact with portions stained by toner or with the image carrying member itself. Furthermore, moving or removing the process cartridge required a significant pulling motion of the process cartridge by the operator from the upper frame to secure that work space, making this work troublesome and creating a defect of difficult jam procedure.
In addition, this invention concerns technology for accomplishing an improvement of handling and maintenance work as well as compactization of an electrophotographic image forming apparatus.
It is desirable to keep the image carrying body of an electrophotographic image forming apparatus, i.e. generally a belt-shaped or drum-shaped body which is referred to as photoreceptor belt or photosensitive drum, in a light-sealed condition at all times because its photosensitivity will diminish when left in a lighted room. Unfortunately, it is necessary to open a part of the outer cover to observe the condition inside and to take proper measures in order to remove or recover jammed papers which occurs around photoreceptor in the image forming apparatus. As a photoreceptor belt or photosensitive drum is deteriorated after being exposed to bright light at that time, the apparatus is designed in such a way that a protective cover, which is provided where the photoreceptor is exposed, is opened and closed according to the opening and closing of the outer cover. However, it is difficult to shut out light completely, and the mechanism becomes complex and leakage of light still occurs. If much time is spent dealing with troubles, then the photoreceptor will actually be exposed without a cover for a long period of time.
In particular, although cartridges have been introduced to areas around the photoreceptor to further compactize the image forming apparatus and improve operability, light sealing measures are not perfect and deterioration of the photoreceptor is not completely eliminated.